NAVAL GEAR DESIGN--THE INTERPRETATION OF SHIP PROPULSION REQUIREMENTS

The Author examines three examples of current naval construction utilizing a General Electric (USA) LM 2500 gas turbine, developing 25,000 hp, with Diesel engines for cruising power. The smallest vessels, about 260 tons, have been ordered by the Indonesian Navy. A three-module gearbox is used, weighting 12.5 tons, and cruising power is provided by two MTU 12V331 Diesel engines. To achieve a power/weight ratio of 2,000 hp/ton the design of rotating and stationary parts has been carefully refined; for example, the primary gearbox has a hollow pinion and idler gears, in which the shafts are welded directly to the gear rim, and fabricated wheels with internal coned plates to resist relatively large transverse and axial forces applied through the bearings. The second example, for the Royal Danish Navy KV class corvettes, is a similar concept, with a single turbine driving dual propellers, but approached from a completely different standpoint. These vessels have a displacement of 1,500 tons and cruising power provided by a single MTU 20V956 Diesel engine of 4,800 bhp. Disconnection of the engine is provided by an oil-operated Ortlinghaus friction clutch, a compact unit capable of accepting the gas turbine overrunning condition on its own. The weight of this gearbox is 44 tons, giving a hp/ton ratio of 570. The third example is the installation for the Italian navy A/S "Maestrale"--class frigates, twin-screw vessels of 2,800 tons displacement and with a gas-turbine power of 50,000 hp. Speed is expected to be some 32 knots. Because the LM 2500 is not made for handed rotation, the gearboxes for port and starboard sets differ. The latter gearbox contains an additional set of "reverse gears" situated between the turbine and the first reduction pinion. The total weight of the combined gearboxes is 72 tons, equivalent to 700 hp/ton. Cruising power is provided by two GMT B230.20 DVM engines, rated 5,500 bhp for continuous operation, and driving through Wichita pneumatic friction clutches. Order from BSRA as No. 49,964.

  • Corporate Authors:

    Whitehall Technical Press Limited

    29 Palace Street, Westminster
    London SW1,   England 
  • Authors:
    • Charles, C J
  • Publication Date: 1978-4

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Filing Info

  • Accession Number: 00194246
  • Record Type: Publication
  • Source Agency: British Ship Research Association
  • Files: TRIS
  • Created Date: Jun 13 1979 12:00AM